(1) Field of the Invention
This invention relates to a control circuit for processing image data received from an imager, with the circuit being useful in providing automatic compensation for those elements associated with the camera or imager.
(2) Background Information
When imaging systems are employed, there several factors which can affect a typical system. Some of these factors are:
1. CCD sensitivity when a Charge Coupled Device is used as the "camera".
2. Certain shortcomings of CCDs, such as dark signal clamp error, dark signal non-uniformity, and photo sensor non-uniformity.
3. Analog signal conditioning relative to drift and gain errors.
4 Lens cosine 4th roll off or non-uniform response of lenses used in the imaging system.
5. Light Emitting Diode (LED) illumination intensity, non-uniformity in illumination, and color balance if LEDs of different colors are used.
6. Thermal effects on the elements included in the imaging system.
It is important to maintain a consistent and stable imaging system to insure that the image data which results therefrom will ensure a predictable post processing performance with regard to binarization, compression, and machine reading.